A process for statically eliminating a charged body by an ionized gas stream has been conventionally performed. Ion gas used for the static elimination is generated by irradiating the X-rays into air or gas. Referring to an X-ray tube for emitting the X-rays, the X-ray tube using beryllium having excellent X-ray transmittance has been known as a transmission window material used for a transmission window for extracting the X-rays from the X-ray tube (Patent Document 1), and the X-ray tube is incorporated in a static elimination device or the like.
The attachment of the transmission window made of beryllium is performed by once reinforcing the transmission window using a metal ring and by attaching the metal ring to a glass vessel body (Patent Document 2). A beryllium plate as the transmission window and the metal ring are adhered by heating the beryllium plate, the metal ring and a brazing material with the beryllium plate on the metal ring via the brazing material (Patent Document 3).    Patent Document 1: Patent Application No. 2951477    Patent Document 2: Japanese Patent Application Laid-Open No. 2000-306533    Patent Document 3: Japanese Patent Application Laid-Open No. 2001-59900